Knowing what belongs—and what doesn’t—inside your compost bin is one of the most important parts of successful composting.
The right ingredients help create rich, healthy compost, while the wrong ones can slow decomposition, attract pests, or even ruin your entire batch.
Whether you’re composting indoors or outdoors, with worms, Bokashi, or a simple pile, this complete list will help you make smarter decisions and avoid common composting mistakes.
Let’s break down what you can definitely compost, what you should compost with caution, and what you should absolutely avoid.
Composting Basics: Greens and Browns
Before diving into the list, here’s a quick reminder of composting’s two core categories:
Greens (Nitrogen-Rich)
These are fresh, moist, and often colorful materials like food scraps. They provide the nitrogen microbes need to grow and multiply.
Examples:
- Fruit and veggie scraps
- Coffee grounds
- Fresh grass clippings
Browns (Carbon-Rich)
These are dry, tough materials that provide energy for composting microbes and help balance moisture.
Examples:
- Shredded paper
- Dry leaves
- Cardboard
A healthy compost pile needs a good balance—typically 1 part green to 3 parts brown.
What You CAN Compost
Fruit and Vegetable Scraps
Includes peels, cores, stems, rinds, and skins from all fruits and vegetables. Chop large pieces to help them break down faster.
Coffee Grounds and Filters
Used coffee grounds are rich in nitrogen. Filters made of plain paper can also be composted (tear them into smaller pieces).
Tea Bags (Paper Only)
Most tea bags are compostable—but double check that they don’t contain plastic. Remove staples and tags first.
Crushed Eggshells
Eggshells are slow to break down but add calcium. Rinse and crush them to help speed the process.
Nut Shells (Except Walnut)
Most shells are compostable if they’re not salted or coated. Avoid black walnut shells, which can be toxic to plants.
Dry Leaves
These are perfect browns. Shred them for faster breakdown and mix them with food scraps to prevent odor.
Shredded Paper
Use non-glossy, black-and-white printed paper. Avoid heavy inks or colored prints. Great for absorbing excess moisture.
Cardboard
Plain cardboard, paper towel rolls, and egg cartons are all compost-safe. Tear them into small pieces first.
Hair and Pet Fur
Small amounts of human or animal hair are fine. Avoid synthetic fibers or large clumps.
Old Flowers and Houseplants
Dead flowers and pruned leaves are safe as long as they’re pesticide-free. Remove any plastic from bouquets first.
Plant-Based Food Leftovers (Minimal Oils)
A little bit of leftover rice, pasta, or bread is okay if it’s not greasy or seasoned heavily.
Compost With Caution
These items may be composted only under certain conditions or with advanced composting systems.
Citrus Peels
They’re compostable but acidic. Use in small amounts, especially in worm bins, to avoid disrupting pH balance.
Onion and Garlic Scraps
These are fine for traditional compost, but worms don’t love them. Use sparingly in worm bins.
Corn Cobs and Husks
These take a long time to break down. Chop or shred them before composting.
Paper Towels and Napkins
If used with food (not cleaning products), they’re usually compost-safe. Avoid if covered in oils or chemicals.
Avocado Pits and Skins
They will compost eventually but take a long time. Break them up to help the process.
Brown Paper Bags
Tear into strips and remove stickers or tape. Avoid printed logos with colored ink.
Bamboo and Wood Utensils
Only compost if labeled 100% compostable and free of chemical coatings.
Seaweed
Great source of minerals, but rinse off excess salt first.
What You SHOULD NOT Compost
These materials cause odor, attract pests, or contain substances harmful to your compost.
Meat, Fish, and Bones
They decompose very slowly, smell terrible, and attract rodents or flies. Avoid completely unless using Bokashi or industrial composting.
Dairy Products
Milk, cheese, yogurt, and butter create strong odors and attract pests. Avoid unless your system is designed to handle them.
Grease, Oil, and Fat
They coat other materials, block airflow, and smell awful. Do not compost any cooking oils or fried food.
Pet Waste (Dogs, Cats)
May contain harmful bacteria or parasites. Avoid entirely in home composting.
Diseased or Moldy Plants
These can spread pathogens or fungi through your compost. Toss them in the trash instead.
Treated Wood or Sawdust
If the wood has been painted, varnished, or chemically treated, it’s not safe to compost.
Glossy or Coated Paper
Magazines, wrapping paper, or any shiny material may contain plastic or heavy metals. Do not compost.
Synthetic Fabric or Dryer Lint
Most lint contains polyester or other plastic fibers that don’t break down.
Vacuum Bag Contents
These often contain synthetic carpet fibers, pet dander, and plastic dust—not compost-friendly.
Plastic Stickers on Produce
Always remove stickers from fruit and veggies before composting the peels.
Tips for Smarter Composting Choices
- Chop and shred materials before composting to speed up the process
- Layer greens and browns for better airflow and fewer odors
- Avoid oversized items that may not break down properly
- Use common sense—when in doubt, leave it out
- Start small and add new materials one at a time to monitor how your system reacts
Printable Quick Reference (Optional)
If you’re composting regularly, create or print a cheat sheet and hang it near your compost bin. That way, everyone in the household knows what’s okay to toss and what isn’t.
You can also label your kitchen scraps container with a short version of this list to help build better composting habits.
Final Thoughts: Composting Starts With Smart Ingredients
Building great compost begins with knowing what to feed your pile. By choosing the right inputs, you support a healthy balance of microbes, keep your compost bin odor-free, and produce nutrient-rich compost faster.
The best composters pay attention not just to what they’re adding—but also to how their pile responds. With a bit of practice, these choices become second nature.
Start with the simple rule: If it grew, it can probably go. Then build your composting skills from there.
Happy composting!